Method of making light sensitive diazo paper for black line image

ABSTRACT

THERE IS PROVIDED A METHOD OF MAKING BALCK IMAGE DIAZOTYPE PRINTS HAVING IMPROVED LONG TERM PRESERVATION PROPERTIES.

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Patent Oflice 3,689,268 Patented Sept. 5, 1972 US. Cl. 96-49 2 Claims ABSTRACT OF THE DISCLOSURE There is provided a method of making black image diazotype prints having improved long term preservation properties.

This is a continuation of US. application Ser. No. 649,- 466, filed June 28, 1967, now abandoned.

BACKGROUND OF THE INVENTION (1) The field of the invention comprises a diazotype printing process for making paper or other sheet material having black images. (2) Heretofore, such black images have been generally made by using phloroglucinol in the developing solution, but owing to the lack of stability of the resulting solution, it was dilficult to preserve the prints over a long term because of their self-coloring property, a result of the oxidation of retained developer. Moreover, such prints also tended to acquire an increasingly dirty background during storage.

This invention was made in order to eliminate entirely these defects, and hence, the developing liquid does not contain phloroglucinol at all.

SUMMARY OF THE INVENTION DESCRIPTION OF THE SPECIFIC EMBODIMENTS Referring further to the developing solution, no deterioration by aging of this developing liquid could be recognized at all during the storage of the liquid, nor during the use, and it enables always the obtaining of a clear white background. For instance, an existing developing liquid and the developing liquid used in this invention were poured into test tubes and tested for forced-aging in oven at 50 deg. centigrade for 24 hours. As a result the former was colored light-brown and became unusable, while the latter, prepared according to this invention, showed entirely no change.

The aromatic diazo compound to be used in this inven tion must have no pre-coupling reaction when preserved in the photosensitive layer with the coexisting blue coupler, and furthermore, it must have immediate color development in 'blue in aqueous alkaline developing solution. These are such as:

4-diazo-2,5-dibutoxy-phenyl-morpholine 4 diazo-2,5-diethoxy-phenyl-morpholine 4diazo-2,5-dimethoxy-phenyl-morpholine 4- diazol-pip eridino-naphthalene 4-diazo-ethyl-b enzyl-aniline 4-diazo-Z-chloro-phenyl-piperidine 4- diazo-2,5 -diethoxy-methyl-benzylaniline 4 diazo-2,5-diethoxy-ethyl-b enzyl aniline 4-cliazo- 3-methyl-hydroxy-ethyl-ethylaniline 4-diazo-2-methyl-monoethyl-aniline 4-diazo-2,S-diethoxy-hydroxyethyl-methylaniline 4-diazo-2-phenoxy S-ethoxy-methylaniline 4- diazo-3-methoxy-diethoXy-aniline 1-diazo-4 4'-methyl) -benzoyl-amino-2,5-diethoxybenzene 1-diazo-4 4'-methoxy) benzoyl-amino-2,5-dimethoxybenzene 1-diazo-4(4'-ethoxy) -benzoyl-amino-2,S-diethoxybenzene With the above compounds, a compound salt thereof with zinc chloride, or the salt of sulfuric acid, gives good results, however, this invention is not of course restricted by the diazo compounds mentioned above. It may be seen that the compounds have a tertiary nitrogen-containing group as well as a diazo group, and that many of them are substituted anilines.

Blue coupler compounds to be contained in the photosensitive layer together with diazo compound as mentioned above are preferably those which do not precouple, and which have faster coupling velocity in addition.

These are such as:

2-hydroxy-naphthalene-3,6-disulfonic acid sodium salt 2-hydroxy-3-naphthoic acid hydroxy ethyl amide 2-hydroxy-3-naphthoic acid dihydroxy ethyl amide 1- (morpholino-acetyl amino)-7-naphthol 1- (morpholino-acetyl amino)-4-naphthol l-biguanidino-7-naphthol-hydrochloride l-biguanidino-2-naphthol-hydrochloride beta-hydroxy naphthoic acid morpholino ethyl amide beta-hydroxy naphthoi-c acid morpholino propyl amide beta-hydroxy naphthoic acid piperidino propyl amide 2-hydroxy-3-naphthoic acid beta-amino ethylamide hydro chloride These blue-producing coupling compounds are recommended for use at a concentration of 0.5-2.0 moles for one mole of the diazo compound. To use more than this recommendation reduces the preservation capability of the sensitizing liquid and of the sensitive paper, and moreover, this'tends to produce a yellow-colored back ground of copy, resulting in a product that is unqualified as marketable goods. Inasmuch as the quantity of used coupler contained in the photosensitive layer of this inven tion, even though it involves a two-component system, is very minute as compared with that used in the dry method (this uses ammonia gas for the development), this amount does not show color by the ammonia-development, or, if repeated several times the image obtainable is unsatisfactory. Referring to the foregoing list of blue couplers, it is apparent that they are hydroxy group-containing derivatives of naphthalene, and that most of them contain an amide group.

As for the yellow coupler to be contained in the developing liquid, at least one selected kind from ethylenediamine- N,N-bisacetoacetamide, acetoacetanilide, m-hydroxy-benzyl alcohol, acetoaceto benzyl amide, m-hydroxyphenyl urea, and acetanilide, etc., is recommended for use in a quite minute quantity, i.e., 2.0 10- --2.0 10- mole for one liter of aqueous alkaline solution. This coupler usually contains an amide group. The alkaline solution is usually made up from potassium carbonate, sodium hydroxide, potassium borate, potassium meta-borate and/ 3 or sodium carbonate, etc. Optimal pH of the solution is approximately 11.5-12.5 for the best color development.

Further excellent preservation power can be obtained by the addition of assistants in the photosensitive layer such as thiourea, cadmium sulfate, and cadmium chloride, and organic or inorganic acids such as oxalic acid, sulfuric acid, tartaric acid, citric acid, and maleic acid etc. at a concentration of 13 percent for a single agent or a mixture, and in addition, by adding 0.5-1 percent of boric acid.

The sensitvie paper obtained by the present invention showed superior preservation capability over a presently marketed sensitive paper of dry type and showed identical preservation power as compared with a paper of semi-wet type. Another feature of the invention is that owing to the minimized use of the coupler, resulting in a decrease in the quantity of unreacted coupler remaining on the copy; in fact, there can be hardly recognized the formation of dirt on the surface during long term preservation of the copy which comes from oxidation of the coupler.

In general, while known sensitive paper of semi-wet type has decreased color-fastness, and has been recognized as not suitable for obtaining copy which is durable over a long term, the copy obtainable by the present invention is durable for long term preservation.

This invention can be understood better by the following examples:

EXAMPLE 1 The following sensitive solution was prepared;

Water-1 liter Sulfuric acid-8 cc.

Cafieine-S grams 2-hydroxy-3-naphthoic acid-hydroxy-ethylamide-3 grams 4 diazo-2,5-dibutoxy phenylmorpholine /2. zinc chloride-11 grams Saponin1 gram Patent pure blue-0.05 gram This solution was coated onto white base paper and was dried. Using an appropirate original picture, this was exposed to light from a fluorescent lamp, was developed 'by using the following developing liquid and thus, a bluish black image was obtained on a clear white background. The preservation property of this light sensitive diazo paper was very excellent with fairly faster color development velocity as compared with existing black light sensitive diazo papers. The developing solution comprised Water-1 liter Potassium carbonate-30 grams Anhydrous sodium thiosulfate--4 grams Ethylene diamine-N,N-bisacetoacetamide0.8 gram This developing liquid was very stable and showed no change, at all, for more than days exposure to air.

EXAMPLE 2 About 20 grams of colloidal silica, and 40 grams of viynl acetate emulsion containing 50 percent solid matter were mixed and dispersed in one liter of water, and this dispersion was pre-coated onto white base paper, followed by coating with the sensitive solution of Example 1. By the procedure of Example 1, there was obtained a highly contrasted image. Color fastness of the developed copy was very excellent, and the copy was durable for permanent preservation. EXAMPLE 3 Following Example 1, if the diazo compound is 15 grams of 4-diazo-l-piperidino-naphthalene /zZnCl and if the blue coupler is a mixture of 1 gram of 2-hydroxy-3- naphthoic acid-hydroxy ethylamide with 2 grams of beta hydroxy naphthoic acid morpholino ethyl amide, this gives a slightly reddish black image of high concentration.

- 4 EXAMPLE 4 Example 1 was followed, except that the diazo compound used was 10 grams 'of 4-diazo-2,S-diethoxy-methyl benzyl aniline /2Z11Cl and the blue coupler was 15 grams of 1-(morpholino-acetylamino)-4-naphthol. This was coated onto precoated paper as described in Example 2. This gave a grayish black image, though the coupling velocity is somewhat decreased, however, this creates no problem in practice.

EXAMPLE 5 A sensitive solution was prepared as follows:

Water-1 liter Oxalic acid20 grams Sulfuric acid1 cc.

1-biguanidino-2-naphthol20 grams 1-diazo-4-(4' methoxy) benzoylamino-2,S-dimethoxy benzene- /2ZnCl -15 grams Saponin1 gram Methylene blue-0.05 gram The above solution was coated on white base paper and then dried. Upon light exposure with an appropriate original picture by means of a high tension mercury lamp, this was developed by the use of alkaline aqueous solution containing 50 grams of potassium meta-borate and 0.3 gram of aoetoacetanilide dissolved in one liter of water, thus obtaining a black image of high concentration.

EXAMPLE 6 In Example 5, instead of the diazo compound, 10 grams of 4-diaZo-ethy1 benzyl aniline /2zinc chloride were used, and 3 grams of beta hydroxy naphthoic acid piperidino propyl amide were used as the coupler, giving a slightly reddish black image.

EXAMPLE 7 In Example 5, instead of the diazo compound, the use of 1-diazo-4-(4'methyl)-benzyl amino-2,5 dimethoxy benzene /2zinc chloride gives an identical result with the former example.

EXAMPLE 8 The pre-coating described in Example 2 was placed on white base paper, followed by the additional coating of the following sensitive solution, and the paper was dried.

The thus obtained photosensitive paper was doubled with an appropriate original picture and was light-exposed by means of a fluorescent lamp copier of 60 watts, followed by color-development with aqueous alkaline solution containing 20 grams potassium carbonate, 30 grams of potassium meta-borate, 1 gram of ethylene diamine-N,N-diacetoamide, and 0.05 gram of acetoacetanilide. There was obtained a slightly bluish black image. The sensitive pa- I per thus prepared gives a considerably concentrated image, and the coupling is increased in speed, which is difierent from existing sensitive diazo paper for black images.

EXAMPLE 9 In Example 8, instead of beta-hydroxy-naphthoic acidmorpholino-ethyl amide used as coupler and contained and this gave an entirely identical result.

EXAMPLE A precoating was made on the surface of whitebase paper by treatment with an aqueous solution composed of 1 liter of water and containing therein 120 grams of finely particulate corn starch of 1-5 microns size, 40 grams colloidal silica of 1-5 microns size, and 80 grams of vinyl acetate emulsion containing 50 percent solid matter. On the thus treated paper the following sensitizing liquid was further coated and the paper dried.

Water-1 liter Concentrated sulfuric acid-7 .5 cc.

Thiourea-10 grams Cadmium sulfate-40 grams 2-hydroxy 3 naphthoic acid-beta-amino-ethyl amidehydro chloride-4 grams 4-diazo 2,5 dibutoxy phenyl morpholine /zzinc chloride7.5 grams Sap0nin-1 gram Patent pure blue0.05 gram On developing the copy according to the manner described in Example 8, there was obtained a sharply contrasted black image with high concentration.

I claim:

1. A method of making a black image containing diazotype print by semi-wet type developing, which comprises preparing a sensitized sheet material by coating said sheet material with a sensitizing solution containing an acid stabilizer and at least one light-sensitive diazonium aromatic compound selected from the group consisting of 4-diazo-2,5-dibutoxy-phenyl-morpholine,

4-diazo-2,5-diethoxy-phenyl-morpholine,

4-diazo-2,5-dimethoxy-phenyl-morpholine, 4-diazo-l-piperidino-naphthalene, 4-diazo-ethyl-benzyl-aniline, 4-diazo-2-chloro-phenyl-piperidine, 4-diazo-2,S-diethoxy-methyl-benzyl-aniline, 4-diam-2,5-diethoxy-ethyl-benzyl-aniline, 4-diazo-3-methyl-hydroxy-ethyl-ethylaniline, 4-diazo-2-methyl-monoethyl-aniline, 4-diazo-2,5-diethoxy-hydroxyethyl-methyl aniline 4-diazo-2-phenoxy-5-ethoxy-hydroxy-methylaniline, 4-diazo-3-methoxy-diethoxy-aniline, 1-diazo-4(4'-methyl) benzoyl-arnino-2,S-diethoxybenzene, 1-diazo-4(4-methoxy)benzoyl-amino-Z,S-dimethoxybenzene and 1-diazo-4(4-ethoxy)benzoyl-amino-2,5-diethoxybenzene and at least one coupling compound selected from the group consisting of 2-hydroxy-naphthalene-3,6-disulfonic acid sodium salt, 2-hydroxy-3-naphthoic acid hydroxy ethyl amide, 2-hydroxy-3-naphthoic acid dihydroxy ethyl amide, l-(morpholino-acetyl amino)-7-naphtho1,

l-(morpholino-acetyl amino)-4-naphthol, 1-biguanidino-7-naphthol-hydroch1oride, 1-biguanidino-Z-naphthol-hydrochloride, beta-hydroxy naphthoic acid morpholino ethyl amide, beta-hydroxy naphthoic acid morpholino propyl amide, beta-hydroxy naphthoic acid piperidino propyl amide, 2-hydroxy S-naphthoic acid beta-amino ethylamide hydrochloride.

said coupling compound being present in the sensitizing solution at a concentration of about 0.5 to 2.0 moles per mol of the diazonium compound, thereby forming a photosensitive layer on said sheet material, drying the sensitized sheet material, exposing the sheet material to a light image, developing the exposed sheet material with an aqueous alkaline developing solution containing at least one coupling compound selected from the group consisting of ethylenediamine-N,N,- bisacetoacetamide, acetoacetanilide, m-hydroxybenzylalcohol, acetoacetobenzylarnide, m-hydroxyphenyl urea and acetoanilide, said coupling compound being present in said developing solution at a concentration of 2.0 10- to 2.0 10- mole/ liter such that a black dye image is formed by the coupling of said coupling compounds with said diazonium compound.

2. The method of claim 1 wherein said developing solution has a pH range of 11.5 to 12.5.

References Cited UNITED STATES PATENTS 2,657,141 10/1953 Kessels 9649 2,688,543 9/ 1954 Von Glahn et al 9691 X 2,776,888 1/1957 Pop 96-91 X 2,789,904 4/ 1957 Benbrook et al. 9649 3,113,025 12/1963 Bialczak 9691 3,123,472 3/1964 Wilders et a1. 9649 3,248,220 4/ 1966 Van Rhijn 9649 X 3,261,684 7/ 1966 Wilders et al 9649 2,776,888 1/1957 Pop 9649 3,248,220 4/1966 Van Rhijn 9691 FOREIGN PATENTS 694,580 7/ 1953 Great Britain 9649 708,204 4/ 1954 Great Britain 9649 937,510 9/1963 Great Britain 9691 937,510 9/ 1963 Great Britain 96-9l OTHER REFERENCES Dinaburg, M. S.: Photosensitive Diazo Compound, 1964, pp. 129-132, relied on.

Kosar, J.: Light-Sensitive System, 1965, pp. 302-303,

relied on.

Van der Grinter: The Diazotype Printing Process, The Photographic Journal, vol. 192B, March-April 1952, pp. 43-48, relied on.

CHARLES L. BOWERS, 111., Primary Examiner U.S. Cl. X.R. 9691 R 

